SCAN0096 - Only 20925 of bound oxygen is unloaded during...

Info icon This preview shows page 1. Sign up to view the full content.

View Full Document Right Arrow Icon
Image of page 1
This is the end of the preview. Sign up to access the rest of the document.

Unformatted text preview: Only 20925% of bound oxygen is unloaded during one systemic circulation If oxygen levels in tissues drop: More oxygen dissociates from hemoglobin and is used by cells Respiratory rate or cardiac output need not increase Hemoglobin Saturation Curve Other Factors Influencing Hemoglobin Saturation Temperature, H+, Pm, and BPG Modify the structure of hemoglobin and alter its affinity for oxygen Increases of these factors: Decrease hemoglobinés affinity for oxygen Enhance oxygen unloading from the blood Decreases act in the opposite manner These parameters are all high in systemic capillaries where oxygen unloading is the goal Other Factors Influencing Hemoglobin Saturation Factors That Increase Release of Oxygen by Hemoglobin As cells metabolize glucose, carbon dioxide is released into the blood causing: Increases in Pm, and H* concentration in capillary blood Declining pH (acidosis), which weakens the hemoglobin—oxygen bond (Bohr effect) Metabolizing cells have heat as a byproduct and the rise in temperature increases BPG synthesis All these factors ensure oxygen unloading in the vicinity of working tissue cells Hemoglobin—Nitric Oxide Partnership Nitric oxide (NO). is a vasodilator that plays a role in blood pressure regulation Hemoglobin is a vasoconstrictor and a nitric oxide scavenger (heme destroys NO) However, as oxygen binds to hemoglobin: Nitric oxide binds to a cysteine amino acid on hemoglobin Bound nitric oxide is protected from degradation by hemoglobinOs iron Hemoglobin—Nitric Oxide Partnership The hemoglobin is released as oxygen is unloaded, causing vasodilation As deoxygenated hemoglobin picks up carbon dioxide, it also binds nitric oxide and carries these gases to the lungs for unloading Carbon Dioxide Transport Carbon dioxide is transported in the blood in three forms Dissolved in plasma 0 7 to 10% Chemically bound to hemoglobin 0 20% is carried in RBCs as carbaminohemoglobin Bicarbonate ion in plasma 0 70% is transported as bicarbonate (HCOy) Transport and Exchange of Carbon Dioxide Carbon dioxide diffuses into RBCs and combines with water to form carbonic acid (HZCOZ), which quickly dissociates into hydrogen ions and bicarbonate ions In RBCs, carbonic anhydrase reversibly catalyzes the conversion of carbon dioxide and water to carbonic acid Transport and Exchange of Carbon Dioxide Transport and Exchange of Carbon Dioxide At the tissues: Bicarbonate quickly diffuses from RBCs into the plasma The chloride shift 0 to counterbalance the outrush of negative bicarbonate ions from the RBCs, chloride ions (Clo) move from the plasma into the erythrocytes Transport and Exchange of Carbon Dioxide At the lungs, these processes are reversed Bicarbonate ions move into the RBCs and bind with hydrogen ions to form carbonic acid Carbonic acid is then split by carbonic anhydrase to release carbon dioxide and water Carbon dioxide then diffuses from the blood into the alveoli Transport and Exchange of Carbon Dioxide Haldane Effect - The amount of carbon dioxide transported is markedly affected by the P02 Haldane effect 0 the lower the P02 and hemoglobin saturation with oxygen, the more carbon dioxide can be carried in the blood Haldane Effect At the tissues, as more carbon dioxide enters the blood: More oxygen dissociates from hemoglobin (Bohr effect) ...
View Full Document

{[ snackBarMessage ]}

What students are saying

  • Left Quote Icon

    As a current student on this bumpy collegiate pathway, I stumbled upon Course Hero, where I can find study resources for nearly all my courses, get online help from tutors 24/7, and even share my old projects, papers, and lecture notes with other students.

    Student Picture

    Kiran Temple University Fox School of Business ‘17, Course Hero Intern

  • Left Quote Icon

    I cannot even describe how much Course Hero helped me this summer. It’s truly become something I can always rely on and help me. In the end, I was not only able to survive summer classes, but I was able to thrive thanks to Course Hero.

    Student Picture

    Dana University of Pennsylvania ‘17, Course Hero Intern

  • Left Quote Icon

    The ability to access any university’s resources through Course Hero proved invaluable in my case. I was behind on Tulane coursework and actually used UCLA’s materials to help me move forward and get everything together on time.

    Student Picture

    Jill Tulane University ‘16, Course Hero Intern